I sell frames and parts fairly consistently over the years so get a good flavour of the market, and I find that everything sells so long as you are competitive on price and honest about condition. I rarely sell full bikes unless the parts are less attractive sold separately.
If it looks like the market has moved downwards, my view is that it’s not coming back and so I take the hit straight away by going in with the lowest price. I’m sure plenty of people have picked up a bargain this way but that’s because of the market rather than me.
Buying and selling again quickly is a surefire way of losing money, which applies to most commodities unless there’s a supply-demand mismatch.
But I also wanted to put in a word for long term ownership, like my two road bikes (2017 & 2019), where after many thousands of miles I am well past what I see as a breakeven point of utility.